Angoh Siow Yan Jennifer, Nergaard Petter Johannes, Jahren Torfinn, Odden Morten, Brainerd Scott Michael
Inland Norway University of Applied Sciences Koppang Norway.
Ecol Evol. 2024 Aug 21;14(8):e70201. doi: 10.1002/ece3.70201. eCollection 2024 Aug.
The pine marten () occupies the northernmost extent of its distribution in Norway, where microtine rodents are an important food item. The relationship between microtine rodent abundance and pine marten population dynamics is not well understood. In this paper, we examined this relationship and tested if environmental factors (e.g. snow depth, elevation, mature spruce forest density and agricultural land density) modulate pine marten population dynamics. We calculated pine marten abundance indices using data collected from 593 unique snow transects surveyed between 2003 and 2014 in Hedmark, Norway. We employed a Partial Rate Correlation Function to identify potential cyclicity in pine marten populations. We did not observe any cyclical patterns in pine marten populations within our short time series. Instead, their population appeared to be directly density-dependent. Although the population growth rate of pine marten tended to increase with increasing elevation, it was not affected by individual variables including a microtine rodent abundance index and snow depth. However, the annual growth rate of pine marten populations was positively affected by the interaction between the microtine rodent abundance index and increasing elevation. Pine marten abundance increased with microtine rodent abundance, elevation, snow depth and density of mature spruce forest, but decreased with increasing agricultural land density. Pine martens are opportunistic diet generalists that can switch between prey and cache food for later consumption. They are also strongly territorial with delayed implantation and are slow to respond to environmental changes due to their relatively low reproductive potential. These life-history traits may mitigate the effects of fluctuating microtine rodent abundance on pine marten reproduction and survival. Nevertheless, our findings suggest that microtine rodents still serve as important prey which can influence the population dynamics of pine martens in higher elevation habitats where alternative prey may be less available.
松貂（）在挪威分布的最北端栖息，在那里田鼠类啮齿动物是其重要的食物来源。田鼠类啮齿动物的数量与松貂种群动态之间的关系尚未得到充分了解。在本文中，我们研究了这种关系，并测试了环境因素（如积雪深度、海拔、成熟云杉林密度和农田密度）是否会调节松貂的种群动态。我们利用2003年至2014年期间在挪威海德马克对593条独特雪道进行调查所收集的数据，计算了松貂的丰度指数。我们采用偏速率相关函数来识别松貂种群中潜在的周期性。在我们的短时间序列中，未观察到松貂种群的任何周期性模式。相反，它们的种群似乎直接依赖于密度。尽管松貂的种群增长率往往随着海拔的升高而增加，但它不受包括田鼠类啮齿动物丰度指数和积雪深度在内的单个变量的影响。然而，田鼠类啮齿动物丰度指数与海拔升高之间的相互作用对松貂种群的年增长率产生了积极影响。松貂的丰度随着田鼠类啮齿动物的丰度、海拔、积雪深度和成熟云杉林密度的增加而增加，但随着农田密度的增加而减少。松貂是机会主义的杂食动物，能够在猎物之间切换并储存食物以供日后食用。它们还具有强烈的领地意识，胚胎延迟着床，并且由于其相对较低的繁殖潜力，对环境变化的反应较慢。这些生活史特征可能会减轻田鼠类啮齿动物数量波动对松貂繁殖和生存的影响。尽管如此，我们的研究结果表明，田鼠类啮齿动物仍然是重要的猎物，在替代猎物可能较少的高海拔栖息地，它们会影响松貂的种群动态。
